Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Strange behavior of red supergiant Betelgeuse smaller and denser than first thought

Strange behavior of red supergiant Betelgeuse smaller and denser than first thought



Betelgeuse illustration

Betelgeuse illustration. Credit: NASA, ESA and E. Wheatley (STScI)

It could take another 100,000 years before the giant red star Betelgeuse dies in a burning explosion, according to a new study by an international research team.

The study led by Dr. Meridith Joyce from The Australian National University (ANU), not only gives Betelgeuse a new lease, but shows that it is both smaller and closer to Earth than previously thought.

Dr. Joyce says the super giant – which is part of the Orion constellation – has long fascinated scientists. But recently, it has been behaving strangely.

“It is usually one of the brightest stars in the sky, but we have observed two drops in the brightness of Betelgeuse since the end of 2019,” said Dr. Joyce.

“This led to speculation that it could be about to explode. But our study provides a different explanation.

“We know that the first attenuation event involved a cloud of dust. We found that the second minor event was probably due to the star’s pulsations. ”

The researchers were able to use hydrodynamic and seismic modeling to learn more about the physics that drives these pulsations – and get a clearer idea of ​​what phase of its life Betelgeuse is in.

According to co-author Dr. Shing-Chi Leung of the University of Tokyo confirmed the analysis “that pressure waves – essentially sound waves – were the cause of Betelgeuse’s pulsation.”

“It’s burning helium at its core at the moment, which means it’s nowhere near exploding,” said Dr. Joyce.

“We could look at about 100,000 years before an explosion happens.”

Co-author Dr. László Molnár from Konkoly Observatory? In Budapest says the study also revealed how big Betelgeuse is and its distance from Earth.

The actual physical size of the Betelgeuse has been a bit of a mystery – previous studies have suggested that it could be larger than circuits about Jupiter. Our results say that Betelgeuse only extends to two-thirds of it with a radius of 750 times the radius of the sun, ”said Dr. Molnár.

“Once we had the physical size of the star, we were able to determine the distance from Earth. Our results show that it is only 530 light-years from us – 25 percent closer than previously thought. ”

The good news is that Betelgeuse is still too far from Earth for the eventual explosion to have a significant impact here.

“It’s still a really big thing when a supernova goes out. And this is our closest candidate. It gives us a rare opportunity to study what happens to stars like this before they explode, ”said Dr. Joyce.

The study was funded by The Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo and facilitated by the ANU Distinguished Visitor’s program. It involved researchers from the United States, Hungary, Hong Kong and the United Kingdom, as well as Australia and Japan.

The study is published in The Astrophysical Journal.

Reference: “Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA” by Meridith Joyce, Shing-Chi Leung, László Molnár, Michael Ireland, Chiaki Kobayashi and Ken’ichi Nomoto, October 13, 2020, The Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / abb8db




Source link